of WE# also begins the programming operation. The
system is not required to provide further controls or
timings. The device will automatically provide an ade-
quate internally generated program pulse and verify
margin. The automatic programming operation is
completed when the data on DQ7 is equivalent to data
written to this bit (see Write Operation Status section)
at which time the device returns to Read mode.
Embedded Programming Algorithm
The Embedded Program Setup is a command only op-
eration that stages the device for automatic program-
ming. Embedded Program Setup is performed by
writing 10h or 50h to the command register.
Once the Embedded Setup Program operation is per-
formed, the next WE# pulse causes a transition to an
active programming operation. Addresses are latched
on the falling edge of CE# or WE# pulse, whichever
happens later. Data is latched on the rising edge of
WE# or CE#, whichever happens first. The rising edge
Figure 2 and Table 5 illustrate the Embedded Program
algorithm, a typical command string, and bus operation.
START
Apply V
PPH
Write Embedded Setup Program Command
Write Embedded Program Command (A/D)
Data# Poll Device
No
Increment Address
Last Address
Yes
Programming Completed
18879C-7
Figure 2. Embedded Programming Algorithm
Table 5. Embedded Programming Algorithm
Bus Operations
Standby
Command
Comments
(see Note)
PPH
Wait for V Ramp to V
PP
Write
Write
Read
Read
Embedded Program Setup Command Data = 10h or 50h
Embedded Program Command Valid Address/Data
Data# Polling to Verify Completion
Available for Read Operations
Note: See AC and DC Characteristics for values of V parameters. The V power supply can be hard-wired to the device or
PP
PP
switchable. When V is switched, V
may be ground, no connect with a resistor tied to ground, or less than V + 2.0 V. Refer
PP
PPL
CC
to Functional Description. Device is either powered-down, erase inhibit or program inhibit.
Am28F256A
13
SPANSION [ SPANSION ]
